The dissociative anesthetic ketamine that acts as an N-methyl-D-aspartate (NMDA) antagonist has been reported to improve neurological damage after experimental ischemic challenges. Here we show that deep anesthesia with ketamine before euthanasia by decapitation improves the quality of neonatal mouse neuronal brain slice preparations. Specifically we found that neurons of the locus coeruleus (LC) and hypoglossal motor neurons had significantly higher input resistances, and LC neurons that generally are difficult to voltage control, could be more reliably voltage clamped compared to control neurons.